Obesity or diabetes: which is more hazardous to the health of the offspring?

OBJECTIVE: To examine impact on perinatal outcome of untreated gestational diabetes (GDM) and non-diabetics stratified by body mass index (BMI). RESEARCH DESIGN AND METHODS: This is a secondary analysis of our investigation of the consequences of not treating GDM. We evaluated 555 untreated GDMs matched to 1100 non-diabetics. BMI was determined using subjects' recalled pre-pregnancy weight. A primary composite variable consisted of stillbirth, neonatal macrosomia/large-for-gestational-age (LGA), neonatal hypoglycemia, erythrocytosis and hyperbilirubinemia. Secondary outcomes included shoulder dystocia, respiratory complications, cesarean delivery and pregnancy-related hypertension.
RESULTS: Untreated subjects in the normal weight category had an ∼2-fold increase for composite outcome and LGA and a 7-fold increase in metabolic complications. The overweight untreated group showed composite outcome, LGA and metabolic complications 2-3-fold higher and induction of labor 5-fold higher. For obese untreated GDMs, significantly higher rates of composite outcome, LGA and metabolic complications, induction of labor and cesarean delivery were 10-, 3-, 5-, 4- and 9-fold, respectively. Perinatal outcome for normal weight untreated GDM was similar to obese non-diabetics.
CONCLUSIONS: Maternal obesity and GDM independently affect adverse pregnancy outcome. The combination has a greater impact than each one alone. However, glycemic level contributes a greater portion to the adverse pregnancy equation.